1. Field of the Invention
This invention relates to a selective ion permeable membrane by photoirradiation utilizing substances which transport ions by absorption of light and an ion transporting method by utilizing the membrane.
2. Related Background Art
Presently, selective permeation of ion has been known as one function of biological membrane, and researches are under progress for obtaining dialysis membranes or various sensors by imparting the function analogous to a biological membrane by such method that a substance having active transportability of an ion is held within a thin film by utilizing such selective permeation. Also, since the membrane utilizing the above principle can be utilized for a device having the function of converting easily the ion concentration difference across the membrane, the so called membrane potential into electrical signals by combination with ion sensitive electrodes, etc., a device by use of said membrane has been proposed to be applied as the chemical device which converts chemical signals to electrical signals. As the device which uses a protein as the ion active transportable substance, for example, a constitution of biochemical device such as sensor for embedding in biological membrane is disclosed in Japanese Patent Laid-open No. 62-11158.
Whereas, if a photoirradiation is used for effecting an ion permeability control, not only the external control method can become easy, but also, for example, a chemical device which can effect photoelectric conversion with small exothermic quantity can be realized. A ion permeable membrane having an excellent volume efficiency and an energy efficiency, maintaining and good controllability is promising in the future as well as the converting device in the field of optical communication.
Also, in controlling a membrane ion permeability by photoirradiation, it is desirable to set the wavelength of the incident light as desired. Further, it is desirable as a matter of course that the membrane ion permeability should not limited to only one direction, but can select the direction of permeation and yet can select it depending on the wavelength of the incident light.
However, at present, no device sufficiently controlled in an ion permeability by photoirradiation has been obtained.